Meta-analysis of adjuvant chemotherapy versus surgery alone in T2aN0 stage IB non-small cell lung cancer

Although there is a strong evidence that adjuvant chemotherapy after surgery was effective in Stages II and IIIA patients involved nonsmall cell lung cancer (NSCLC), its eligibility in Stage IB disease has been unknown. Therefore, this meta-analysis was aimed to compare the effects of adjuvant chemotherapy versus surgery alone in patients with Stage IB NSCLC.

We systematically searched for articles from their inclusion to July 2016. An article search was performed in PubMed, Embase, Medline, and Cochrane Library. Irrelevant literature was excluded with the preferred reporting items for systematic reviews and meta-analysis standards. Overall survival (OS) was the primary end-point, which was defined as the time from randomization until death from any cause; our second end-point was disease-free survival (DFS). All analyses were based on intention-to-treat.

Six randomized controlled trials with total of 2007 patients were included in present meta-analysis. The results were expressed as risk ratios (RR) with 95% confidence intervals (CIs). Compared to surgery alone, patients can benefit from adjuvant chemotherapy after surgery in terms of 5-year OS (RR = 1.19; 95% CI, 1.03-1.37; P = 0.02) and 5-year DFS (RR = 1.36; 95% CI, 1.13-1.63; P = 0.001). There was no significant difference in terms of benefit according to certain patient characteristics, such as age, gender, tumor histology, smoking history, and resection type.

Adjuvant chemotherapy after surgery was beneficial to the patients with Stage IB disease in terms of OS and progression-free survival. Therefore, we recommend clinicians to take this treatment strategy into account for the patients with Stage IB NSCLC.